A redox flow battery is one of core products closely associated with renewable energy, reduction of greenhouse gas, a rechargeable battery and a smart grid, which are attracting the greatest interest in the world in recent years and a product which is rapidly leading to expansion of the market worldwide.
Currently, the human obtains most of its energy from fossil fuels, but there is a problem in that the use of these fossil fuels has serious adverse effects on the environment, such as air pollution and global warming, and low energy efficiency. In order to solve the problems according to the use of the fossil fuels, recently, interest in renewable energy has rapidly increased. Interests and research on such renewable energy are being actively conducted not only in domestic but also worldwide.
The renewable energy market reaches maturity at home and abroad, but there is a problem in that an amount of energy generated is largely changed according to an environmental influence such as time and weather due to the characteristic of the renewable energy. As a result, the supply of an energy storage system (ESS) which stores renewable energy generated is required in order to stabilize development of the renewable energy, and the redox flow battery has attracted attention as the large-capacity energy storage system.
As illustrated in FIG. 1, a general structure of the redox flow battery is constituted by a stack 1 in which cells with electrochemical reaction are stacked, a tank 3 storing an electrolyte, and a pump 4 supplying an electrolyte to the stack from the electrolyte tank.
FIG. 2 illustrates an exploded perspective view of the general stack 1 and illustrates an end plate 11, an insulating plate 12, a current plate 13, a separator 14, a gasket 15, a flow frame 16, an electrode 17, a gasket 15, an ion exchange membrane 18, a gasket 15, an electrode 17, a flow frame 16, a gasket 15, a separator 14, a current plate 13, an insulating plate 12, and an end plate 11, in order from the left side.
Unit cells are formed from the separator 14 to the separator 14 and the gaskets 15 in the stack will be omitted if necessary. In general, one stack is formed by stacking tens to hundreds of unit cells.
The present invention relates to a stack structure capable of supplying an electrolyte using a capillary tube, and in this regard, in U.S. Pat. No. 8,293,390 B2 and US 2011/0206960, there is disclosed a technique capable of supplying an electrolyte to a stack using a capillary tube.
However, in U.S. Pat. No. 8,293,390 B2, an ion exchange membrane (a separator) is deformed by a tube, and in this case, the ion exchange membrane needs to be a material capable of maintaining sealing such as a gasket.
Also, in US 2011/0206960, there is disclosed a method of sealing a connection portion of a capillary tube, but in this case, there is a problem that the connection portion can not be disassembled again.